Rotary drill string apparatus



Dec. 9, 1958 H. W.,THORNBURG 2,863,638 ROTARY DRILL STRING APPARATUS VOriginal File'dAug. 14, 1953 5 Sheets-Sheet l COMPRESSOR HEREm' W.THoRNwRq,

IN VEN TOR.

ATTORNEQ.

H., w. THORNBURG 2,863,638

ROTARY DRILL STRING APPARATUS Original Fi] ed Aug. 14, 1955 Dec. 9, 19585 Sheets-Sheet 2 m U m .m T.. W T w R E H INVENTOR.

ATTORNEY.

H. w. THORNBURG ROTARY DRILL STRING APPARATUS original Filed Aug. 14,195s Dec. 9, 1958 5 Sheets-Sheet 3 HERBERT WJRoRNsoRa,

ATTORNEY United States Patent ROTARY DRILL STRING APPARATUS `HerbertW.`Tfhornbiirg, South Milwaukee, Wis., assignor to Bucyrus-Erie Company,South Milwaukee, Wis., a corporation of Delaware 6 Claims. (Cl. Z55-19)This invention relates to well-drill equipment and more particularly tonew and useful improvements 'in drillstring apparatus for rotary-typeblast-hole drills.

This invention is a divisional of copending application Serial No.374,364, iiled August 14, 1953, for Rotary Well Drill.

The principal objects of the invention are to provide an improveddetachable rotary drill-string apparatus iu which:

(l) A tlexible coupling between the rotary driving unit and the drillpipe provides with limited transverse flexibility a direct positivetorque drive and pull-down connection and at the Sametime a passage forcompressed air supplied to the drill bit.

(2) The upper end of the drill pipe is automatically locked againstrotation relative to the drive shaft responsive to the compressed .airsupplied to the string.

(3) The drill-pipe joints will break before the joint between the drillpipe and rotary-driving unit, eliminating the need for tool wrenches tohold the driving unit-drill pipe joint while unscrewing of thedrill-pipe joints during take-down of the drill string.

(4) The uppermost drill-pipe joint is self-tightening, and automaticallylocked against unscrewing. l

In addition to the principal objects above stated, a number of novel anduseful details have been worked out which will be readily evident as thedescription progresses.

The invention consists in the lnovel parts and in the combination andarrangement thereof, which are defined in the appended claims, and ofwhich one embodiment is exemplified in the accompanying drawings, whichare hereinafter particularly described and explained.

Throughout the description the same reference-number is applied to thesame member or to similar members.

Figure 1 is a side elevation, partly in section, showing therotary-power unit, rotary-drive coupling and tool wrench on therotary-drive coupling.

Figure 2 is a vertical section taken along line 2--2 of Figure 3,showing the ilexible coupling connected to the drill pipe and showingthe tool wrench engaged with the upper end of the drill pipe.

Figure 3 is a horizontal section, taken along line 3 3 of Figure 2,showing the tool wrench which is associated with the rotary-drivecoupling.

Figuref4 is an enlarged plan view of Figure 2, taken along line 4-4 ofFigure 5, showing the upper split collar of the flexible coupling boltedin place, and in cross section, the lower resilient washer andinterlocking teeth of the tlexible coupling in driving contact duringclockwise rotation of the drive shaft.

Figure 5 is an enlarged Vertical section view taken along line 5-5 ofFigure 4, showing the assembled elements of the exible coupling, and theinterconnection between the uid conduits, plungermechanism and pawlswhich engage with the upper end of the drill'pipe section adjacent therotary drive coupling.

Turning now to the gures, Figure 1 vshows the drill "ice string of therotary-type blast-hole drill shown and described in my copendingapplications, Serial No. 374,364, tiled August 14, 1953, for Rotary WellDrill, and Serial No. 464,471, filed October 25, v1954, for Well DrillPipe-Handling Apparatus, which are hereby incorporated by referenceherein.

From Figure 1, it is seen that frame 30, which is vertically movablewith Vreference to the supporting fixed mast 14 (fully described in saidlcopending applications), carries the rotary-drive machineryV for thedrill-pipe l34 and the coupling 33 and that coupling 33 provides notonly a rotary-drive connection, but also a supporting connection, to thedrill `pipe so that the drill .pipe can be raisedand lowered as well asrotated.l .Frame 30 is v-operatively connected to the rotary-'drill mastby pinions 36 meshing with a vertical rack on the mast (not shown),and-is raised and lowered under power of cables (not shown) reeved onshipper-shaft-drum 37 keyed to shippershaft 3S rotatably Amounted onframe 30, all of which is more particularly shown and described in myaforementioned copending applications.

`Drill pipe 34 is made `up of oneor more tubular drillpipe sectionsdetachably connected one to another by threaded joints. A rotary drill`bit (not shown) vis thread- Ajoint connected to the lower-end of thelowermost drillpipe section. l

Reversible electric motor 31 is drivably connected, through reductiongears 97a, 97h, and 97C, to gear 98 which is splined to shaft 99 ofrotary-drive unit 32.1 The lower end of shaft 99 is connected bycoupling 33 to the upper end of the drill string.

Referring to Figures '1, r2, 4 and 5, the flexible coupling 33 will nowbe described.

Driving flange 33a is built integral with the lower end of shaft 99 andis provided with a plurality of depending downwardly projecting teeth33b (Figure 5) spaced near the periphery of said flange 33a. A pluralitylof corresponding upwardly projecting teeth 33C near the periphery of`the upper face of socket 33d register with teeth 33b on ange 33a toprovide torsional driving connection to socket 33d. The teeth 33e areheld in interlocking engagement with -teeth '33b in the followingmanner.

Annular resilient washer 33g is fitted over vthe lower end of shaft 99and is spaced between the upper `face of socket 33d and the lower faceof ange 33a. Annular resilient washer 33h is tted over shaft 99 adjacentthe upper face of ange 33a. A split annular collar 33e (Figure 4) isfitted adjacent the upper yface of resilient washer 33h (Figure S). Capscrews 331 extend vertically downward through holes 33j, bored in splitcollarI 33e, through enlarged holes 33k bored in ange 33a to registerwith holes 33]',1and are threaded vertically downward into teeth 33e atthreads 331 tapped in socket `33a! to secure split collar 33e to saidsocket. By tightening cap screws 331, split collar 33e and socket 33dare rigidly connected, resilient washers 33g and 33h areplaced undercompression, and teeth 33b and 33C vare interlocked, but are providedwith some vertical spacing between the top surface of each tooth and thebottom surface of its corresponding notch due to the thickness ofresilient washers 33g and 33h. Split collar 33e and bolts 33j, whichrigidly connect said collar and socket 33d, take the tension in hoistingthe drill line.

The lower portion of socket 33d (Figures l and 5) is threaded to make athreaded joint with. the top drill pipe'fsection 34 at threads 21 and27, and carries a drill pipe gripping mechanism (hereinafter described)for locking said drill pipe section to socket 33d.

The resilient washers 33g and 33h provide a laterally and axiallyflexible coupling between the rotary drive unit 32 and the drill pipe34, so that the head of the 3 drill string may wobble slightly, andvibrations in the drill string are absorbed instead of being transmitteddirectly into the Arotary drive mechanism. Whenever there is a lateraldeflection of drill string 34, the resilient washers 33g and 33h permitthe joint to bend, but engagement between teeth 33b and 33C is retainedfor applying torque to the drill string. In this respect, the couplingis similar to a universal joint. If the drill string, for example, islaterally dellected to the left in Figure 5, socket 33d will pivot aboutthe-center of central core 102, and resilient washer 33h will be furthercompressed between ange 33a vand split collar 33e on the right side ofthe coupling and said washer will expand on the opposite side of thecoupling. Meanwhile `resilient washer 33g on the right side of thecoupling will expand, and on the opposite side of the coupling saidwasher will be further compressed between socket 33d and ange 33a.Resilient washer 33g will absorb any shock in the coupling created byvertical bouncing of the drill string, and also acts as an air-tightseal between central core 102 of the drive shaft 99 and central annularchamber 102a. -Chamber 102a is bored axially from the bottom of socket33d and narrows in diameter near the top of said socket to register withcentral core 102. Resilient washer 33h will similarly absorb any shockin the coupling in a downward direction caused by downward movement ofthe drill string relative to the coupling.

Although these resilient washers provide a limited ilexibility under`compression and lateral forces, a rotary drive coupling is alwaysmaintained between teeth 33b and 33C. The fact that there is clearancebetween the sides of the teeth opposite their sides that are in drivingengagement, and the further fact that there is Vertical clearancebetween the tips of teeth 33b and 33C and the respective bottom surfaceof their corresponding notches n allow the teeth limited lateral andvertical shifting movement relative to each other.

Flexible pressure-fluid conduit 100 (Figure l) extends from a compressor(not shown) to pressure Huid-tight seallng ring 101 on rotary-drive unit32. The upper end of central core 102 (see Figures 2 and 5), extendingaxlally of shaft 99, registers with conduit 100 (Figure 1) and makes afluid-tight connection therewith at pressure fluid-tight sealing ring101. Central core 102 extends from pressure fluid-tight sealing ring 101through coupllng 33 and makes a fluid connection with central core 103of drill pipe 34.

Referring to Figures 2, 3 and 5, a drill-pipe gripping mechanlsmconsisting of two pawls 151 mounted on either side of the lower end ofrotary-drive coupling socket 33d to pivot about horizontal pins 153 isemployed to engage the upper end of the uppermost drill-pipe sectlonjust below its connection to the rotary-drive coupllng 33.

Each pawl 151 s actuated by the downward extension of lts correspondingplunger 154 bearing against the upper horizontal surface of said pawloutwardly of the center of its horizontal pin 153 (Figure 5) to rotatesaid pawl inwardly at its lower end and engage notches 155 1n the upperend of the top section of drill pipe 34, each of said notches beingformed to receive its corresponding pawl 151 to permit only right-handor clockwise rotation of the rotary drive coupling relative to saiddrill pipe (Figure 3).

Each plunger 154 tits into a corresponding chamber 158 formed ondiametrically opposite sides of socket 33d. Port 157, which is boredvertically from the upper end of each chamber 158, makes a fluidlconnection between the upper end of chamber 158 and a transversepassage 156,

said passage being bored radially near the upper end of socket 33d andis sealed by plugs 162 (see Figures 4 and 5 Passage 156 opens intocentral annular chamber 102a'in socket 33d. Fitted above plunger 154inchamber `158 is an air seal 154:1 to prevent leakageof air pastplunger 154. Each plunger 154 is` actuated by compressed ving dirt androck chips from the drill hole.

air which passes from supply conduit into central core 102 of coupling33, then through transverse passages 156 and port 157 into chamber 158in which the plunger 154 is seated. Pawls 151 are normally held in theiroutward position (dotted outline in Figure 5) by coil springs 159(Figures 3 and 5 Each respective plunger 154 rests against the upperouter horizontal edge of its matching pawl 151. The vertical line ofcontact between plunger 154 and pawl 151 is outward of the center ofrotation of horizontal pin 153, which is the pivot point of pawl 151.Therefore, whenever plunger 158 is actuated downward by compressed air,each pawl 151 is rotated inwardly to engage the top drill pipe section34 at a notch 155. During drilling compressed air or other iluid isforced through central core 102, central core 103 of drill pipe 34 andout through theb ottorn of the drill bit into the drill hole. This is aconventional means ofscaveng- The fluid pressure used to clear materialfrom the drill hole is also used to actuate and seat pawls 151 of thewrench. Pawls 151 are automatically actuated by plunger 154 to engagethe drill pipe as soon as fluid pressure is lbuilt up in the core of thedrill string. When so engaged the pawls will, due to the notches, permitright-hand or clockwise (Fig. 3) rotation of the rotary drive couplingto screw the coupling threads onto the threads of the upper drill pipesection, but will lock the rotary driving coupling against unscrewingfrom the drill pipe counterclockwise relative to the drill pipe when therotary drive rotates the drill pipe in a left-hand or counterclockwisedirection of rotation. This permits right-hand threads 27 on the upperend of drill pipe 34 to screw into corresponding threads 21 of coupling33 and tighten the joint between coupling 33 and drill pipe 34 whilepawls 151 are engaged, but prevents threads 21 and 27 from unscrewing,and the joint from loosening during takedown of the drill string.

During drilling and make-up of the drill string, the rotary driverotates the drill string in the right-hand or clockwise direction (Fig.3). During take-down of the drill string, the section of drill pipeadjacent the uppermost drill-pipe section is held stationary by a toolwrench (shown in Fig. 22 of my copending application, Serial No.464,471, tiled October 25, 1954), and the rotary drive rotates in theleft-hand or counterclockwise direction, unscrewing the joint betweenthe stationary drillpipe section and the uppermost drill-pipe section.

When air pressure is shut off, springs 159 between coupling 33d andcollar 160 of pins 153 bias each pawl 151, so that pawls 151 willnormally return to disengaged position (shown in phantom lines in Fig.2), and thereby bias plungers 154 to return to their retracted positionin chamber 158 (see Fig. 5).

A further feature of the invention is that bevel face 25 at the lowerend of each drill-pipe section 34 (Figure 2), makes horizontal shoulder26, at said lower end of drill pipe 34, smaller in diameter thanshoulder 22 at the upper end of each drill-pipe section 34. -Shoulder22a on coupling 33 is of the same diameteras shoulder 22 on the upperend of drill-pipe section 34. Accordingly, the contact between shoulders22 and 26 will have less friction resistance to unscrewing than theContact between shoulders 22 and 22a, and hence the lower thread-jointwill normally break before the upper thread-joint at coupling 33. Shouldthe next lower joint become stuck or frozen and thus fail to breaklirst, the drill pipe gripping mechanism is available for standby use tolock the upper joint against unscrewing. By turning on the air supply,

vwhich is fed through -central core 102 (Fig. 2), pawls described, itisto beeunderstoo'd that the invention is not to be limited to thespecific form or arrangement of parts as herein described and shown, orspecifically covered by the claims.

I claim:

1. In a detachable torque-drive coupling device for coupling a rotarydrive power means and the uppermost tubular drill-pipe section of arotary drill string for transmitting rotation thereto and absorbinglateral and axial vibrations, the combination of: a rotary drive memberassociated with said rotary drive power means; a driven member having adetachable rotary-drive connection with the upper end of said uppermostdrill-pipe section; interlock means providing a loose laterally ilexiblerotarydrive connection between said driving member and said drivenmember; a first pair of axially-opposed lateral bearing surfaces locatedone on and adjacent the lower end and the other on and adjacent theupper end of the driving and driven members respectively; firstresilient means interposed between said first pair of bearing surfaces,said first resilient means being subjected to axial compression by saidfirst pair of bearing surfaces when said driving and driven members arein mutual compression; a coupling member detachably connected inaxiallyxed relation to one of said driven and driving members; a secondpair of axially-opposed lateral bearing surfaces located one on saidcoupling member and the other on the other of said driven and drivingmembers; second resilient means interposed between said second pair ofbearing surfaces, said second resilient means being subjected tocompression by said second pair of bearing surfaces when said drivingand driven members are in mutual axial tension; a longitudinal hollowcore for the passage of pressure fluid extending longitudinally throughsaid driving member, said driven member, and said coupling member, tosaid uppermost drill-pipe section; said first resilient means forming aseal between the driving and driven members to prevent the escape ofpressure fluid from said longitudinal hollow core.

2. A torque-drive coupling device according to claim 1, furthercharacterized by having a drill-pipe gripping mechanism mounted on saiddriven member, and pressure fluid responsive actuating means having apressure uid connection with said longitudinal hollow core andoperatively connected to said drill-pipe gripping mechanism toautomatically actuate said mechanism by pressure fluid in said hollowcore to engage the uppermost drill-pipe section and lock it againstrotational displacement in one direction relative to said driven member.

3. A torque-drive coupling device according to claim 2, furthercharacterized by the fact that the drill-pipe mechanism includes a pairof pawls adapted to engage cooperating notches on said uppermostdrill-pipe section.

4. A torque-drive coupling device according to claim 3, furthercharacterized by having resilient means operatively connected to saidpair of pawls biasing said pawls to normally disengage the uppermostdrill-pipe section.

5. In a detachable torque-drive coupling device for coupling a rotarydrive power means and the uppermost tubular drill-pipe section of arotary drill string, for transmitting rotation and vertical movementthereto, the

combination of: a rotary drive member associated with said rotary drivepower means; a driven member having a disengageable rotary-driveconnection with the upper end of said uppermost drill-pipe section; arotary-drive connection between said driving member and said drivenmember; a longitudinal hollow core for the passage of pressure uidlongitudinally through said driving member and said driven member tosaid uppermost drill-pipe section; a drill-pipe gripping mechanismmounted on one of said members, and pressure-fluid responsive actuatingmeans having a pressure-fluid connection with said hollow core andoperatively connected to said drill-pipe gripping mechanism toautomatically actuate said mechanism by pressure iluid in said hollowcore to engage the uppermost drill-pipe section and lock it againstrotational displacement in one direction relative to said driven member.

6. In a detachable torque-drive coupling device for coupling a rotarydrive power means and a rotary drill string for transmitting rotationaland Vertical movement thereto, the combination of: a rotary drive memberassociated with said rotary drive power means; a driven member; a rotarydrive connection between said drive member and said driven member; adrill-pipe section adapted to form the uppermost drill-pipe section ofsaid rotary drill string; said uppermost drill-pipe section havingthreads at its upper and lower ends, one an inner thread and the otheran outer thread, for threaded joint connections to the rotary drivemember and the next lower drill-pipe section of the rotary drill string,and having a cooperating friction contact surface adjacent each of saidupper and lower threads adapted to have cooperating contact withopposing friction surfaces on said rotary drive member and said nextlower drill-pipe section; said rotary driven member having a thread forsaid threaded joint connection with the uppermost drill-pipe section,and being engageable and disengageable therewith by rotation of saiddriven member about its axis relative to said uppermost drill-pipesection; and a cooperating friction contact surface at the lower end ofthe driven member adjacent the threaded joint connection between thedriven member and the uppermost drill-pipe section having cooperatingfriction contact with the cooperating friction contact surface at theupper end of the uppermost drill-pipe section when the last-mentionedthreaded joint connection is substantially engaged; the area of suchcooperating friction contact being greater than the area of thecooperating friction contact surface at the lower end of the uppermostdrill-pipe section.

References Cited in the le of this patent UNITED STATES PATENTS1,728,111 Elms et al Sept. 10, 1929 1,857,528 Cantell May 10, 19321,960,688 Archer May 29, 1934 1,983,545 Johnson Dec. 11, 1934 2,439,751Olsen 1 Apr. 13, 1948 2,620,165 Crickmer Dec. 2, 1952 2,765,147 VertsonOct. 2, 1956

